Which statements about tsunamis are true?
they can occur only in water.
they can occur in water and on land.
we can predict them.
underwater landslides can cause them.
dam failures can cause them.

They can occur only in water.

We can predict them.

Underwater landslides can cause them.

Explanation:

A tsunami is the result of abrupt tectonic processes in oceanic areas. When an interaction occurs between two tectonic plates, causing a high intensity earthquake in a marine relief, the result is the formation of a large wave, the tsunames. This is the main cause of this kind of natural disaster. The others are rare, and consist of falling asteroids in the water and eruptions of marine volcanoes. There are software capable of identifying tsunami formation. This is a work of geologists. For example, Japan's tsunami was forecast in 2011, but there were still many deaths.

They can occur only in water

Underwater landslides can cause them

dam failures can cause them

Explanation:

It is basically referring to where they form and not what they can hit, so they can not occur on land. Underwater landslides and dam failures create a giant ripple effect. Tsunamis are just massive ripples in water.

electromagnetic shielding is the practice of reducing the electromagnetic field in a space by blocking the field with barriers made of conductive or magnetic materials. shielding is typically applied to enclosures to isolate electrical devices from their surroundings, and to cables to isolate wires from the environment through which the cable runs. electromagnetic shielding that blocks radio frequency electromagnetic radiation is also known as rf shielding.

the shielding can reduce the coupling of radio waves, electromagnetic fields and electrostatic fields. a conductive enclosure used to block electrostatic fields is also known as a faraday cage. the amount of reduction depends very much upon the material used, its thickness, the size of the shielded volume and the frequency of the fields of interest and the size, shape and orientation of apertures in a shield to an incident electromagnetic

from wikipedia

t = 1/400 h   ⇔ 0.0025 h ⇔ 9s ⇔ 0.15 m

any of the answers are correct.